Christopher ate 2 slices of pie. Daniel ate 2 slices. If Christopher ate $\dfrac{2}{5}$ of the pie, what fraction of the pie is remaining?
Explanation: If 2 slices represent $\dfrac{2}{5}$ of the pie, there must have been a total of 5 slices. $\text{fraction of pie remaining} = \dfrac{\text{number of slices remaining}}{\text{number of slices total}}$ Together they ate 4 slices, which leaves 1 out of 5 slices remaining. There is $\dfrac{1}{5}$ of the pie remaining.